list1 =[]; 
cities={
    '北京':{
        '朝阳':['国贸','CBD','天阶','我爱我家','链接地产'],
        '海淀':['圆明园','苏州街','中关村','北京大学'],
        '昌平':['沙河','南口','小汤山',],
        '怀柔':['桃花','梅花','大山'],
        '密云':['密云A','密云B','密云C']
    },
    '河北':{
        '石家庄':['石家庄A','石家庄B','石家庄C','石家庄D','石家庄E'],
        '张家口':['张家口A','张家口B','张家口C'],
        '承德':['承德A','承德B','承德C','承德D']
    }
}
for i in cities['河北']:
    print(i)
for i in range(10):
    list1.append(i)
    print(list1)
    
a, b = 0, 1
while b < 10:
    print(b)
    a, b = b, a+b